This invention relates to a color recognition apparatus for effectively confirming any color change of a product in a drug production line, an inspection line or the like, and to a process for automatic inspection of foreign matter contamination and of the configuration of such a product as well as for efficiently determining a color code printed on or attached to articles or goods such as a tire, an electric wire, a food package, and a resistor or the like.
It has heretofore been (customary) to check for color changes of products and to inspect whether foreign matter has been mixed therewith by means of a method employing the naked eye of an operator so as to ensure the quality of products in a drug production line, inspection line or the like. There are difficulties involved in such a visual inspection, however, since uniform color discrimination cannot be made and (the operator) may not be instantaneously aware of the presence of foreign matter to allow for the removal thereof due to individual differences.
There has been a well known black-and-white photographic apparatus that is adapted to obtain the video image of an object and then to picture process the video signal obtained from a picture treatment with the density of the video, that is, differences in lightness, thereby allowing a hue to be identified. An apparatus of this class is not capable of color discrimination when there is no difference in lightness even if the hue of the object is different.
For this reason, an optical filter corresponding to the color of the object is mounted on the black-and-white photographic apparatus so as to obtain a difference in density for the purpose of detecting a color. The problems arising from this type of apparatus are that much labor is required for treating the object if it has a multiplicity of colors, thus necessitating the adjustment of the optical filter each time.
A form of color recognition which is performed using of a color photographic apparatus has also been well known. This requires color separation in which a color is separated into the three primary colors such as red (R), green (G) and blue (B) and performs a mutual operation for the respective color compositions to obtain color recognition, thereby departing from (the need for) a sensual decision on the basic of vision. This also requires much labor for color correction each time in the color photographic apparatus. In addition, the (need for a) transmission path for each color composition requires three systems and thus the apparatus is complicated and very costly. It would be desirable to solve these problems.
In these days, various articles such as electrical wire, food packages, and resistors have a multi-colored marking line (stripe, circle, etc.,) printed or attached thereto, this being known as a color code. These colored marking lines are different from each other according to the type, grade and the like of the product. In other words, the type, grade and the like of the product may be discerned by identifying the order or arrangement of hues which form these marking lines.
A well known type of hue detection apparatus for such marking lines and the like employs a color separation light receptive element as disclosed in Japanese Laid-open Patent Application Nos. 80018/1986 and 80019/1986. A chroma detection apparatus of the disclosed type is limited to hue detection of only a small part of the hue location of the object whose hue is to be detected. This type of hue detection apparatus therefore requires the movement of the object whenever the order or arrangement of hues successively disposed in the form of marking lines is detected so that the portion to be hue detected may be scanned. This requires much time for recognizing the hue of the marking line and leads to shortcomings in that the hue is not determined and processed at high speed. It is thus eagerly hoped that this (problem) can be solved.